In related art sewing machines, when forming buttonhole stitches, a buttonhole stitching pattern is selected from a plurality of stitching pattern (see, e.g., JP 5-049773 A and JP 7-284587 A).
In related art sewing machines, stitching data for a plurality of stitching widths are prestored in a memory of a control device so that a stitching width can be selected in accordance with a shape or a size of a button, or a use of a workpiece. When a user inputs a desired stitching width, it is possible to read stitching data that corresponds to the input stitching width from the memory, and a buttonhole stitching is carried out based on the stitching data read from the memory.
However, in the related art sewing machines, a plurality of sets of stitching data corresponding to the number of widths that can be stitched are prepared and stored in the memory in advance. Therefore, a size of the stitching data to be stored in the memory is enormous so that a memory having a large capacity is required. Thus, a cost increase is unavoidable. On the other hand, when a capacity of the memory is reduced, the number of sets of stitching data that can be stored also reduces. Thus, it is difficult to flexibly meet user's needs.